CODEWITHSUNDEEP
c#linqlambda
user118190
user118190

Reputation: 2179

How to optimize this LINQ expression w/ Where condition and calling Method?

I am seeking any advice or tips on the following method I have that is using LINQ to find a certain property in a Collection that is null and then go through the results (sub-list) and execute a method on another property from the same Collection.

private void SetRaises()
{
    if (employeeCollection != null)
    {
      var noRaiseList = employeeCollection .Where(emp => emp.Raise == null).ToList();
      foreach (var record in noRaiseList )
      {
         CalculateRaise(record);
      }
    }
}

public void CalculateRaise(Employee emp)
{
    if (emp!= null)
        emp.Raise = emp.YearsOfService * 100;
}

The part I don't like in the first method, SetRaises(), is the following snippet:

foreach (var record in noRaiseList )
{
    CalculateRaise(record);
}

Is there a way to integrate that part into my LINQ expression directly, i.e. some extension method I am not aware of?

Thank you!

Upvotes: 2

Views: 145

Answers (4)

Maris
Maris

Reputation: 4776

It should be something like this:

var noRaiseList = employeeCollection .Where(emp => emp.Raise == null).ToList().ForEach(e=>e.Raise = e.YearsOfService * 100);

Upvotes: 0

Abbas
Abbas

Reputation: 14432

You could use the ForEach chain-method. But that's only sugar syntax.

employeeCollection.Where(emp => emp.Raise == null)
                  .ToList()
                  .ForEach(record => CalculateRaise(record))

Upvotes: 0

gzaxx
gzaxx

Reputation: 17600

If you don't need list of employees without Raise you can do this in one line:

employeeCollection.Where(emp => emp.Raise == null).ToList().ForEach(x => x.Raise = x.YearsOfService * 100);

Upvotes: 0

Marc Gravell
Marc Gravell

Reputation: 1063058

The first thing you could do would be: don't generate an intermediate list:

 var pending = employeeCollection.Where(emp => emp.Raise == null);
 foreach (var record in pending)
 {
     CalculateRaise(record);
 }

which is identical to:

 foreach (var record in employeeCollection.Where(emp => emp.Raise == null))
 {
     CalculateRaise(record);
 }

This is now non-buffered deferred execution.

But frankly, the LINQ here isn't giving you much. You could also just:

foreach(var emp in employeeCollection)
{
    if(emp.Raise == null) CalculateRaise(emp);
}

Upvotes: 5

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